The present invention relates to a heat-development-type color light-sensitive material, and more particularly to a heat-development-type color light-sensitive material whose transfer image has a high maximum density with little fog and excellent color separability.
The color photographic process which uses a conventionally known light-sensitive silver halide is superior in the light-sensitivity, gradation, image preservability, etc., to different other color photographic processes, and has been most extensively used to date. The color photographic process, however, because wet process is applied to its processing including development, bleaching, fixing and washing, has many such disadvantageous problems that it takes time and costs much labor in the processing, its processing chemicals are possible to harm the human body and also possible to pollute the processing room and operator's body, and the disposal of its waste liquids is laborious and costly.
For this reason, development of a method for the formation of color images by dry process has been strongly demanded.
Heat-development-type black-and-white light-sensitive materials, whose development is effected by heating, are conventionally known and described in, for example, Japanese Patent Examined Publication Nos. 4921/1968 and 4924/1968 disclosing those light-sensitive materials comprising organic silver salts, silver halides and developing agents. Further there are also known a variety of heat-developable color light-sensitive materials developed on the basis of such heat-developable black-and-white light-sensitive materials.
For example, U.S. Pat. Nos. 3,531,286, 3,761,270 and 3,764,328, and Research Disclosure Nos. 15108, 15127, 12044 and 16479 describe those heat-developable light-sensitive materials containing photographic couplers and color developing agents; U.S. Pat. No. 3,180,731, and Research Disclosure Nos. 13443 and 14347 describe those which use leuco dyes; U.S. Pat. No. 4,235,957 and Research Disclosure Nos. 14433, 14448, 15227, 15776, 18137 and 19419 describe those which apply the silver dye bleach process; and U.S. Pat. Nos. 4,124,398, 4,124,387 and 4,123,273 describe methods for the heat bleaching of heat-developable light-sensitive materials.
These proposals relating to heat-developable color light-sensitive materials, however, are hardly capable or totally incapable of bleaching or fixing the simultaneously formed black-and-white silver image, or even if capable of bleaching or fixing, they require a wet processing or the like. Accordingly, these proposals hardly enable the formation of clear color images or require a troublesome post-treatment, and thus no favorable one is found among these proposals.
On the other hand, those color light-sensitive materials designed to give a color image by transferring the diffusible dye released by heat development are disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 179840/1982 (corresponding to U.S. Pat. Nos. 4,463,079), 186744/1982 (U.S. Pat. Nos. 4,474,867), 198458/1982 (EP-66,282), 207250/1982 (EP-67,455), 40551/1983 (U.S. Pat. Nos. 4,430,415), and 58543/1983 (EP-76,482), and disclosed also in our Japanese Patent O.P.I. Publication Nos. 12431/1984 and 229649/1982. These proposals are such that a dye donator having a diffusible dye in the same molecule thereof releases the diffusible dye as a result of the heat-developing reaction of an organic silver salt, and the released dye is then transferred to the image receiving layer, whereby a color image can be obtained. In the present specification such color light-sensitive materials are called "dye-releasing-type" color light-sensitive materials.
Also on the other hand, the proposals described in our Japanese Patent O.P.I. Publication Nos. 124339/1984 and 159159/1984 are such that a colorless or light-color dye donator reacts with the oxidized product of a color developing agent produced as a result of the heat-developing reaction of an organic silver salt to thereby form a heat-diffusible dye, which is then transferred to the image-receiving layer, whereby a color image is obtained. Such color light-sensitive materials are herein called "dye-forming-type" color light-sensitive materials.
In order to obtain a multicolor image on the image-receiving layer by the diffusion transfer of dyes by heating without requiring a wet processing, the color light-sensitive material, whether it is of the dye-forming type or of the dye-releasing type, is considered advantageous to be of the multilayer construction similar to that of conventional color light-sensitive materials.
To take a printing light-sensitive material as an example of conventional color light-sensitive materials, in the case of a color photographic paper, usually in order from the bottom layer, a blue-sensitive layer containing an yellow coupler, a green-sensitive layer containing a magenta coupler, and a red-sensitive layer containing a cyan coupler are formed. And in the case of a diffusion transfer-type printing material, the bottom layer is a cyan dye-donating red-sensitive layer, then a magenta dye-donating green-sensitive layer, and then an yellow dye-donating blue-sensitive layer are provided in the described order. In addition, interlayers for the purpose of preventing the colors from mixing are provided between the layers, and in most cases an yellow filter layer is provided between the blue-sensitive layer and the green-sensitive layer.
Also in heat-development-type color light-sensitive materials, in order to effect full color reproductions, a multilayer construction similar to the above will be necessary. In the case of a heat-development-type color light-sensitive material, however, if the superposed multilayer construction is adopted, there arises a problem that the bottom layer's dye is not completely transferred to the image-receiving layer, causing a transfer trouble of the dye from the bottom layer.
At the same time the light-sensitive material has the disadvantages that, due to its undesirable multilayer effect, the fog of, particularly, the lower layer, i.e., the layer located further from the image-receiving layer, increases as compared to the case of a single layer one, and its color separability is inadequate. Thus, the improvement of these disadvantages has been strongly demanded.